The present invention relates generally to golf club assembly and maintenance and, more particularly, to an apparatus for fitting a handgrip over and onto the free end of a golf club shaft.
A golf club has a shaft with a club head at one end and a handgrip at the opposite free end of the shaft. The shaft is a straight, elongated rod or tube fabricated from a suitable material. Contemporary shafts are typically made from an aluminum alloy or a graphite composite. The typical handgrip is a hollow tube open at one end and usually substantially closed at the other end except for a small vent. The handgrip is usually made from an elastomeric material which can be stretched, with some difficulty, over the free end of the shaft for installation onto the shaft. The vent allows air to escape from the handgrip during fitting and aligning of the grip on the shaft.
With use, a golf club""s handgrip deteriorates and must be replaced, from time to time, during the useful life of the club. Fitting a new handgrip as a replacement grip on an old club involves stripping the old grip from the free end of the club shaft, cleaning the shaft of an adhesive used to bind grips to the shaft, preparing the shaft to receive a new grip and then fitting the new grip over the free end of the shaft. Preparing the shaft for a new grip may involve application of fresh adhesive to the shaft, which sometimes includes wrapping the shaft with double sided tape. The new handgrip then must be pulled down onto the shaft, or the shaft end inserted into the grip.
The handgrip itself is usually made so that in a unstretched condition it has a slightly smaller interior diameter than the outside diameter of the shaft end it is to be fitted to. This necessitates stretching the grip to fit the grip onto a shaft. If tape has been wound on the shaft, pulling the grip down over the shaft can result in localized contact between the interior of the grip and the tape and in pulling the tape apart in areas where the winds of the tape overlap. This can result in the wind of the tape becoming locally stretched or bunched up, producing a feeling in users of the club of an uneven grip. The presence of wound tape on a shaft exaggerates the problem of evenly fitting new handgrip to a shaft so that the grip exhibits a good feel to the user and is highly stable in its position.
Numerous patents have been issued directed to the problem of fitting grips to golf club shafts. Several references have dealt with methods of using air pressure, either as a vacuum applied around the exterior of the grip or as over pressure inside the grip, to expand the grip sufficiently to allow it to be easily slipped over the free end of a shaft. The air pressure can then be released to allow the grip to contract around the shaft. In general, the objectives are to provide quick, secure and accurate positioning of grips to clubs.
U.S. Pat. No. 5,429,706 to Cresse et al., illustrates one use of compressed air to inflate and thereby swell a handgrip allowing shaft and grip to be easily mated. Cresse et al., observes that the closed end of a handgrip typically has a small orifice. Where no orifice exists, the grip can be easily pierced to provide one. Cresse et al. supply a support body which has a nipple insertable through the orifice from outside of the grip. Air under pressure is introduced to the inside of the grip through the nipple after first introducing the shaft sufficiently to seal the interior of the grip.
An object of the invention is to provide a mechanically simple handgrip fitting and aligning apparatus usable on a work bench.
Still another object of the invention is to provide a mechanism which eases insertion of golf club shafts into handgrips.
The invention provides an apparatus for radially expanding an elastic handgrip on its axis of elongation to allow easier introduction of a shaft to the elastic handgrip by an open end of the shaft. The apparatus has two principal sections including a main body which provides a central plenum which cradles a grip being installed on a shaft. A second section is a tail stock section having a cup disposed to receive one end of the elastic handgrip. The main body and the tail stock section align on one another end to end, but are not directly connected to one another, allowing the spacing between the sections to be adjusted for different sized grips. A ventilation probe extends from the center of the cup in the tail stock section forward for introduction to the grip. A laser sighting aid is installed in the tail stock section. A grip end wedge tool fits around a shaft and is positionable in the main body near the end opposite to the end proximate to the tail stock section.
Further provided are a source of compressed air and an attachment between the source of compressed air and the ventilation probe for delivering air under pressure to an interior of an elastic handgrip under the control of the user.
Additional effects, features and advantages will be apparent in the written description that follows.